NHibernate-使用Criteria API对整数列进行LIKE搜索的最简单方法? [英] NHibernate - easiest way to do a LIKE search against an integer column with Criteria API?

问题描述

我正在尝试对整数列进行类似搜索，实际上，我需要将该列转换为varchar，然后进行类似搜索.这可能吗?使用Criteria API最简单的方法是什么?

I'm trying to do a like search against an integer column, what I need to do is actually cast the column to a varchar and then do the like search. Is this possible? what's the easiest way to do this using the Criteria API?

var search = "123";
criteria.Add(Restrictions.Like("Number", "%" + search + "%"))

推荐答案

如果Number是一个字符串，那将很容易:

If Number were a string, then it would be easy :

.Add(Restrictions.Like("Number", "some_value",MatchMode.Anywhere))

因为有数字，NHibernate会检查Number的类型，如果您给它提供一个字符串，它将抛出异常.

Since you have a number, NHibernate will check the type of Number and if you give it a string it will throw an exception.

不确定NH团队为什么不提供以对象作为参数和MatchMode参数的重载....

Not sure why the NH team didn't provide an overload with object as parameter and a MatchMode parameters ....

无论如何，您仍然可以像这样:

Anyhow, you can still do it like this :

.Add(Expression.Sql("{alias}.Number like ?", "%2%", NHibernateUtil.String))

修改

关于别名:

(我找不到文档讨论的地方，但这是我对它的理解)

(i can't find where the documentation talks about this but here's my understanding of it )

{alias}返回NH内部为最新CreateCriteria使用的别名.因此，如果您有:

{alias} returns the alias used inside by NH for the most recent CreateCriteria. So if you had :

session.CreateCriteria<User>("firstAlias")
       .CreateCriteria("firstAlias.Document", "doc")
       .Add(Expression.Sql("{alias}.Number like ?", "%2%",  
                           NHibernateUtil.String)).List<User>();

{alias}在这种情况下将是'doc'-因此，您最终将得到:doc.Number.

{alias} in this case would be 'doc' - so you would end up with : doc.Number .

因此，请始终在需要使用其别名的CreateCriteria之后使用{alias}.

So, always use {alias} after the CreateCriteria whose alias you need to use.

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